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Wavy Lenses Extend Depth of Field in Digital Imaging
Posted by
CmdrTaco
on Tue Mar 18, 2003 12:37 PM
from the optimize-this dept.
from the optimize-this dept.
genegeek writes "On Feb 25 CDM Optics was awarded a patent for a new digital imaging system utilizing "Wavefront Coding" that produces images with 10-fold the depth of field of conventional lenses. The image itself is blurred until processed. Image examples are here."
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So (Score:4, Insightful)
Personally, I will stick to analog photography.
Re:So (Score:3, Interesting)
I mean this has it's advantages, perhaps not to the average joe. I like analog photography too, but digital will work much better in getting images from space probes, satellites, and other far off devices, hell, even spy-planes, to another location really quickly.
Re:So (Score:5, Interesting)
You stick to your film. I'll stack my Nikon D1X against your 30-year-old camera any day of the week, personally. And that's not even top of the line anymore -- Canon has a new 11MP camera that puts any 35mm camera to shame.
Just because $300 consumer digicams are crap doesn't mean that digital hasn't already surpassed film. It's just a matter of making it affordable now.
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Re:So (Score:3, Informative)
Film and digital resolution comparisons (Score:5, Interesting)
http://www.robgalbraith.com/bins/content_page.a
http://www.luminous-landscape.com/reviews/camer
This may just change someone's opinon on how digital compares to film. I know it made me rethink the "conventional wisdom" that many more pixels are needed to reproduce film detail.
Cheers,
Jeremy
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Re:Film and digital resolution comparisons (Score:5, Informative)
and: http://www.luminous-landscape.com/reviews/cameras
It's just polite to make such links both active and accurate (extraneous spaces in both links -- probably inserted by slashdot because you tried to submit the URLs as plain text).
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Re:So (Score:3, Informative)
It's been shown in side by side tests of large prints that 10-11Mp is far superior to 35mm film. Despite 35mm being technically able to hold more information than that, the grain of the film causes the images to come out looking worse.
Re:So (Score:5, Informative)
Don't get me wrong: I *love* my Canon PowerShot G2 (4MP). I've been extremely pleased with the results in a 4x6 format. I've blown up some as large as 8x10 (had them professionally printed and developed) and find that the quality is almost as good as prints made from 100 ISO 35mm film. Having "during the shot" color balancing also makes it much easier to get useable prints without serious headaches. And it's certainly more conveinent to me to have the images digitally available, too.
I also find that without my old-school mental block of "don't waste film" is gone, and that I now take many more shots than I used to. It leads to a bigger choice of shots to choose from, so I now get better final prints. Yes, I know I wasn't supposed to worry about "wasting film" before, but those old habits are very hard to break.
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Re:So (Score:4, Insightful)
Or, lets take wide-angle pictures. With the cropping factor on your Nikon D1X, how can you be any wider than say 32mm (35mm equivalent).
Digital is great, but in some cases, 35mm cameras are still superior. Especially low-light and wide-angle photography.
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Re:So (Score:4, Informative)
I've made 20"x30"s from this camera with no complaints. They weren't razor-sharp, but then again neither are 35mm prints at that size. Yours will be a bit sharper, but mine will have no grain and better color. Which one is better is a matter of opinion. And against Canon's 11MP, you wouldn't have a prayer.
Or, lets take wide-angle pictures. With the cropping factor on your Nikon D1X, how can you be any wider than say 32mm (35mm equivalent).
I have a 17mm lens (17-35mm F/2.8 AFS), which is 25mm equivalent on the D1X. If I went down to Nikon's rectlinear 14mm, I'd get 21mm equivalent. That's certainly wide enough for almost any application.
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Re:Digital has better colour? What??? (Score:5, Insightful)
This is what we refer to as "argument by bizarre definition".
Slide film captures color via photochemicals that change in response to light. Digital cameras capture color via sensors that signal in response to light. Saying that one is better "by definition" is patently absurd.
If slide film is inherently perfect, why are there so many different slide films with different color responses? If slide film captures color "exactly as it was", why is Fuji Velvia widely known for producing great landscape shots but murdering skin-tones? Slide film has all the same color concerns that any other capture method has -- good red response but poor greens, or great blues but muddy purples, for instance. Nothing is perfect, especially when the only real way to judge them is using the also-imperfect human eye.
I'm not basing my "better color" assertion on a bizarre definition of the abstract ideal. It's just my opinion, but I hold that my professional digital SLR, with little or no post-processing, produces better color than anything the film world has to offer. "Good color" is a subjective thing, and while you may disagree with me about that (cite examples please!), I stand by my statement.
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Noise floor and linearity (Score:5, Interesting)
One person mentioned that Fuji Velvia is great for landscapes but murders skin tones. This is because the sensitivity curve of a digital can be easily optimized, while it's very difficult to tweak the sensitivity and linearity of films based on chemical reactions.
As to rounding to the nearest bit - There's a lower limit in both electronic and film recording of the precision that a light level can be recorded which is distinguishable from noise. This is called the "noise floor" - Use enough bits, and then all the bit roundoffs will be well below the noise floor of even film media. (Which does indeed have a noise floor, just as digitals do. The nice thing about digitals is that with improved electronics and sensors, the noise floor of the sensor is dropping while film is staying the same. One of the things "pro" digitals are known for is having far less noise than lower-end digitals, and those improvements are constantly moving down to the consumer level.)
And for those that WANT the nonlinearities/quirks of film - All a camera manufacturer has to do is model the nonlinearities of major film types and then they can easily be emulated, just like guitar amps that use modeling techniques to emulate older units.
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Analog 'tricks' are still better though. (Score:5, Insightful)
Photoshop is great software, but no matter how much I try, basic manipulation (on b&w images particularly), especially brightness/contrast adjustment and dodging/burning, always gives me much better results under an enlarger. Same for exposure effects; Photoshop's solarize filter is good, but there's just some intangible warmth and...analog-ness to a well-solarized paper print. Maybe it's just the random scatter and size of the grain of film against the gridded regularity of the digital images, or the slight variation in quality across the print (not imperfect, but not...digitally homogenous), but for purely aesthetic ends, I have to go with film and paper.
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There's more to life than Photoshop (Score:3, Informative)
There are some interesting HDR (high dynamic range) projects, such as HDRShop [debevec.org], and these
HDRI vs RGB (Score:3, Informative)
High Dynamic Range Images use a higher bit depth (12 bits per chanel?). Many of the Nikon cameras can save out these 12 bit/channel images, which, with the proper manipulation software (HDRShop, others) can be used for much finer and subtler manipulation.
So, (math skills permiting), I make that out as 4096 levels per ch
Re:So (Score:3, Insightful)
Re:So (Score:3, Interesting)
Realize that the Canon 1Ds has pixels that are SMALLER than the airy disc size at almost all f/stops. You simply cannot achieve better resolution with the lenses available.
Believe what you want about your 135 film, but it takes APERTURE to shrink the airy disc and improve the true image resolution. As
Depends on the film (Score:3, Interesting)
Now, show me a digital camera that can do 4096x3192 / 10 bpc / 125 fps and I will be impress
Re:So (Score:4, Insightful)
I can shoot in in extreme cold and extreme heat. What's the temp rating on your batteries?
I can choose the light sensitivity I need for my shooting conditions, bound only by the speed of the film available to me. How fast, in ISO numbers, is your CCD? I can get 3200, 6400 or higher. And for special effects I can go infrared.
My permanent storage is both cheaper and more permanent than yours over the long term.
Finally, a lot of Pulitzer shots are extra shots that were initially unpublished. Digital storage invites a photographer to erase that which the editor rejects. Film doesn't.
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Re:Gimme a break (Score:4, Informative)
I've blown 6MP images up to 20"x30". They look great. Good enough that people gush about how great they look when they buy them from us, at least. While I don't have access to an 11MP camera, I can't imagine that 30"x40" would be too much of a stretch.
Keep in mind that I'm talking about images from a $5000 camera, not a piece-o'-crap point-and-shoot.
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Re:So (Score:5, Insightful)
Don't think this is a big deal? I'm into amateur photography, and I have a camera that I only bought 9 months ago that I've taken 1500 shots with. Have I kept them all? No. Have I printed them all? No.
And that's the point, for me. I paid $1k for a camera, and now I can take as many pictures as I'd like, without having to pay for it every damn time. The pictures that I do want printed, I can get done for very reasonable prices at places like Shutterfly. And the ones that turn out bad, or I just don't feel like printing, cost me exactly $0.
Do some math. How much would I have spent on film and processing for a traditional 35mm camera in the last 9 months, had I gone that route instead of the digital? By my reckoning, it'd be at least $500, if not more, depending on the quality of the film I purchased. Within another year or so, the camera will have paid for itself, if only in reduced cost per image.
And as for artistic purposes
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Re:35mm (Score:3, Insightful)
Low-yeld (Score:3, Informative)
I doubt its that bad, since a camera can deal with a sparkling of 'dead' sensors, while pretty much any defect will kill a CPU.
Re:So (Score:5, Informative)
The advantage of this system over your Canon is that you can get high depth of field and large apertures at the same time. In order to increase the depth of field of your camera, you have to stop down the lens, which means less light. Less light means longer exposures (can't stop the action) or more sensitive film/sensors (more noise).
Instead of stopping down the lens and blocking light, this only affects the phase of the wavefront which means all the light energy still goes through.
Extremely clever.
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Re:So (Score:3, Informative)
Last time I checked, it was a hell of a lot easier to do photo processing tricks with photoshop than in a darkroom, and with experience and skill the two types of work can be hard to distinguish from each other. The only exception I can think of being "push" type processing which takes advantage of being able to stretch or alter the dynamic range of your medium (film or photopaper) beyond its ratings. Since the site appears
Not everyone has a darkroom. (Score:5, Insightful)
I loved shooting pictures for the college newspaper, because that meant that whatever leftover film I had from the shoot, I could take those extra shots and develop those slides.
Now, with digital, I never have to worry about developing film, or buying new film, so the cost of me getting a camera went down a significant amount. On top of that, I never had to worry that the shots I take didn't quite come out right. I have an instant look at the shot I had.
Once the SLR bodies on the digitals go down in price a bit more, I'll be able to shoot pretty much whatever I was able to shoot with an analog camera. (With the exception of slide film.)
Also, the digital camera is much more environmentally friendly. All those chemicals you use during processing gotta go SOMEWHERE.
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Re:So (Score:5, Interesting)
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Thundercats (Score:4, Funny)
I'd settle for X-ray glasses.
Down already, hrmm... (Score:5, Funny)
Digital photography needs LESS DoF, not MORE. (Score:5, Insightful)
I guess an extremely deep DoF is preferable in some cases, but in a lot of photography, it is desirable to use a shallow DoF in order to throw everything other than the subject out of focus (making for a nice, pleasing, soft background and drawing attention to the subject). This is very difficult to do with small-sensor digital cameras.
So I wonder if these "wavy lenses" can be used "in reverse" to narrow the depth of field for the purposes of enhancing creative DoF control?
Cheers,
Jeremy
Re:Digital photography needs LESS DoF, not MORE. (Score:4, Insightful)
In the end, I would rather have to throw away extra data rather than never have the data in the first place.
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Re:Digital photography needs LESS DoF, not MORE. (Score:5, Informative)
I've never met a consumer-grade digital camera with decent aperature range or depth of field. IMHO the new "wavy lens" technology can only be of benefit. (Assuming it actually works.)
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Re:Digital photography needs LESS DoF, not MORE. (Score:3, Interesting)
What we want is control of depth-of-field. Lenses produce different effect in the out-of-focus parts of the image. There are great debates about the quality of this part of the image. Some of the best lenses for great "bokeh" are made by Leica.
Space Tech Spinoff Again! (Score:3, Informative)
I couldn't help but think back to the problem with the Hubble Space Telescope [nevada.edu], wherein after the launch they discovered that the mirror had not been properly ground to specification.
very cool (Score:5, Informative)
Here's a bit of background: in photography or laser scanning (point-by-point photography, basically), you always have a trade-off between depth-of-field and aperture size (as any photographer knows). Bigger aperture means shallow depth-of-field. However, a smaller aperture means lots of wasted light (imagine closing the aperture in your camera), and this means longer exposure times, and more importantly more NOISE in your images. This is true for digital, film, or photodetector.
So the "holy grail" is to keep the aperture open but still have high depth-of-field. This system depends on changing the phase of the light, instead of the amplitude (which is what you do when you stop down a lens to a smaller aperture). That way, no light energy is blocked and wasted.
Since the phase is changed, the resulting image on the CCD or film is fuzzy and has to be "decoded". You can think of it as "encoding" the wavefront in a special way that preserves the depth of field, capturing the image, and then "decoding" it into a sharp picture. It is really amazing. I hope it shows up in consumer cameras someday, it could completely change consumer photography since most "snapshot photographers" don't care about depth of field or all that stuff. It will also be great for medical and industrial imaging.
My system was sort of a hybrid between shading the aperture (instead of a sudden stopping of light, it gradually goes to black at the edge) and phase changes. Lots of people have been working on this problem over the years, but these guys really stripped the problem down to the essence and came up with a highly optimized solution.
Re:very cool (Score:4, Funny)
I did my master's research in extended depth-of-field optics
Was he a cruel master, or a tough but fair one? :) </lame>
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What?! (Score:5, Funny)
What about the deep focus movies of the 50's? (Score:3, Interesting)
Re:What about the deep focus movies of the 50's? (Score:4, Interesting)
1) Throw a shitload of light on the scene (This is what they did for the effects work on "Darby O'Gill and the Little People..Peter Jackson eat your heart out)
2) Use a diopter, a lense that changes focal length split down the middle, so that half the image is at 20mm, and the other half is at 120mm (for instance). This was a trick pioneered by Orson Wells, I beleive.
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Wow, a good patent (Score:4, Funny)
NASA docking camera? (Score:3, Interesting)
I'd go and find it but NS archives are subscription only. I really ought to get round to subscribing, I buy it often enough...
-Baz
what is more interesting to me as a photographer.. (Score:5, Interesting)
is this: Can this technology be used to control (not just increase, but also decrease) depth of field at image processing time? More specifically, can I get selective focus *after* creating the image? In criticizing my own work, I ususally wish I had openned up for *less* depth of field. I realize that sports photographers don't have this problem
University site with original papers (Score:4, Informative)
"Economist" article (Score:4, Informative)
http://www.economist.com/science/tq/displayStory.c fm?story_id=1476751 [economist.com]
Re:first and still /. ed? (Score:5, Funny)
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Re:first and still /. ed? (Score:5, Funny)
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It's a php page serving images (Score:3, Informative)
I hope the heatsinks work!
Re:first and still /. ed? (Score:3, Funny)
Yeah, but the text is real sharp, isn't it?
Re:Offline (Score:5, Funny)
Could this mean that, I shudder to say,
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Quick Depth of Field tutorial (Score:4, Informative)
This technology doesn't take a fundamentally blurred image and sharpen it; instead it looks like it uses very precisely waved lenses to create interference in the light coming through the lens, which is then digitally deconstructed to provide a sharp image with a VERY deep DoF. I can't get to their site to read up on this, but I'd guess there's probably some sort of differential-focus setup (2 lenses, focused at either end of your DoF, generating interference) and a lot of Fourier transforms. But that's just an educated guess based on what I know about optics and waveforms - YMMV, my $0.02, caveat emptor, IANAL, and I haven't had PhysChem in a year. Feel free to add any other disclaimers I left out.
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